1. Field of the Invention
The present invention pertains to the construction of a trigger sprayer in which all of the component parts are made of plastic and the number of component parts is reduced, thereby reducing the construction cost of the trigger sprayer. In particular, the present invention pertains to a trigger sprayer that replaces the separate liquid inlet and liquid outlet valves of conventional trigger sprayers with a single valve member having an inlet valve element and an outlet valve element positioned inside the pump chamber of the trigger sprayer. The trigger sprayer eliminates the metal coil spring and the separate liquid spinner of conventional trigger sprayers, giving it an eight piece construction.
2. Description of the Related Art
Handheld and hand operated liquid dispensers known as trigger sprayers are used to dispense liquid products, such as cleaning liquids. A trigger sprayer is typically connected to a bottle containing the liquid. The liquid is dispensed from the bottle by manual operation of the trigger sprayer.
The typical construction of a trigger sprayer includes a sprayer housing that is connected to the neck of the bottle. The sprayer housing is typically connected to the bottle neck by a threaded connection or a bayonet-type connection. The sprayer housing is molded of plastic and is formed with a pump chamber, a liquid supply passage communicating with the pump chamber, and a liquid discharge passage communicating with the pump chamber. A pump chamber opening on the exterior of the sprayer housing provides access to the pump chamber interior. A liquid supply opening on the exterior of the sprayer housing communicates through the liquid supply passage with the pump chamber interior. A liquid discharge opening on the exterior of the sprayer housing communicates through the liquid discharge passage with the pump chamber interior.
A dip tube is connected to the sprayer housing at the liquid supply opening. The dip tube extends into the liquid contained in the bottle when the sprayer housing is attached to the bottle. The dip tube communicates the liquid in the bottle with the liquid supply passage in the sprayer housing and with the interior of the pump chamber.
A nozzle assembly is assembled to the sprayer housing at the liquid outlet opening. Some nozzle assemblies include features that enable the adjustment of the pattern of the liquid discharged from the trigger sprayer. For example, a nozzle assembly that includes a separate liquid spinner and a rotatable nozzle cap that can be adjusted between an “off” position where discharge from the trigger sprayer is prevented, and one or more “on” positions where liquid discharge from the trigger sprayer is permitted, and the liquid discharge can be adjusted between a spray, stream, or foam pattern of discharge.
A pump piston is inserted into the pump chamber through the pump chamber opening on the sprayer housing. A metal coil spring is typically inserted inside the pump chamber and engages with the pump piston. The pump piston is mounted in the pump chamber for reciprocating movements between charge and discharge positions of the piston in the pump chamber. Moving the piston into the pump chamber to the discharge position compresses the spring, and the liquid in the pump chamber is forced through the liquid discharge passage and out of sprayer housing through the nozzle assembly. When the piston is moved out of the pump chamber to the charge position by the spring pushing against the piston, a vacuum is created in the pump chamber that draws liquid through the dip tube and through the liquid supply passage into the pump chamber.
A trigger is mounted the sprayer housing for movement of the trigger relative to the sprayer housing. Typically, the trigger pivots relative to the sprayer housing. However, other types of movement are possible. The trigger is operatively connected to the pump piston to cause the reciprocating movements of the pump piston in the pump chamber in response to movements of the trigger.
Inlet and outlet check valves are assembled into the sprayer housing. The inlet check valve controls the flow of liquid through the liquid supply passage to the pump chamber, and prevents the reverse flow of liquid. The outlet check valve controls the flow of the liquid from the pump chamber through the liquid discharge passage, and prevents the reverse flow of liquid.
The typical construction a trigger sprayer described above is comprised of many different component parts. The manufacturing of each of these separate component parts and the assembly of these component parts into the sprayer housing of the trigger sprayer all contribute to the total manufacturing cost of the trigger sprayer. If the number of component parts of the trigger sprayer can be reduced, and if the assembly of the component parts into the sprayer housing of the trigger sprayer can be simplified, the manufacturing cost of the trigger sprayer can be reduced.